This is the 1286th most frequent Polish word.
kilkunastu
"Kilkunastu" means "several" or "a dozen or so" (used for numbers between 11 and 19).
The word 'kilkunastu' here quantifies the number of students, suggesting an approximate count of about a dozen.
W bibliotece jest kilkunastu studentów czytających książki.
There are a dozen or so students reading books in the library.
The word 'kilkunastu' is used to estimate the number of apples purchased, implying a range close to twelve.
Kupiliśmy kilkunastu jabłek na targu.
We bought around twelve apples at the market.
'Kilkunastu' in this context quantifies people who attended, providing an approximate range slightly above ten.